1. Field of the Invention
This invention relates to a magazine for accommodating a plurality of recording media in an electron microscope. This invention particularly relates to a recording medium magazine for accommodating stimulable phosphor sheets which are housed in holders.
2. Description of the Prior Art
Electron microscopes have heretofore been known wherein an electron beam which has passed through a sample is refracted with an electric field or a magnetic field in order to obtain enlarged images of samples. In general, the electron microscope is provided with a camera chamber. A recording medium such as photographic film is positioned in the camera chamber and exposed to an electron beam which has passed through a sample in order to record an electron microscope image of the sample on the recording medium.
In cases where the recording medium is photographic film, a single sheet of photographic film is housed in a cassette and used to record an electron microscope image. After the recording of the electron microscope image is finished, the cassette is taken out of the camera chamber. The photographic film is then taken out of the cassette and subjected to development processing.
The applicant proposed in U.S. Pat. Nos. 4,651,220 and 4,847,497 novel systems for recording and reproducing an electron microscope image wherein, instead of photographic film being used, a stimulable phosphor sheet as disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318 and 4,387,428 and Japanese Unexamined Patent Publication No. 56(1981)-11395 is utilized as a recording medium. Basically, the proposed systems for recording and reproducing an electron microscope image comprise the steps of (i) exposing a stimulable phosphor sheet to an electron beam which has passed through a sample in a vacuum in order to store the energy of the electron beam on the stimulable phosphor sheet, (ii) thereafter exposing the stimulable phosphor sheet to stimulating rays or the like in order to release the stored energy in the form of emitted light, (iii) photoelectrically detecting the emitted light to obtain an image signal, and (iv) using the image signal to reproduce an electron beam image of the sample.
Also, as disclosed in U.S. Pat. No. 4,889,990, a novel electron microscope has been proposed wherein photographic film or a stimulable phosphor sheet is selectively used as a recording medium in a single camera chamber.
In general, a plurality of recording media such as photographic film or stimulable phosphor sheets are housed in a feed magazine which is located in an electron microscope. The recording media are fed one after another from the feed magazine and located at a recording position where a recording medium is exposed to an electron beam. Recording media on which electron microscope images have been recorded are sequentially fed into a housing magazine which is capable of housing a plurality of recording media.
The applicant also proposed in Japanese Patent Application No. 62(1987)-317732 now U.S. Pat. No. 4,926,016, a magazine for housing both recording media on which no images have been recorded and recording media on which images have been recorded. The proposed magazine comprises a medium housing rack which is composed of a plurality of medium housing compartments each of which compartments houses a single recording medium. The medium housing rack can be moved vertically. A housing means is provided to push a recording medium, which is located at a predetermined height, out of the rack and to move a recording medium into the rack. Because a single magazine houses both unused recording media and used recording media on which images have been recorded, the number of magazines which are to be provided in an electron microscope can be kept small.
However, actually, photographic film is housed in a cassette when it is used in the camera chamber. On the other hand, stimulable phosphor sheets are used without being housed in cassettes because, for example, it is necessary for the stimulable phosphor sheets to be bent and conveyed when they are subjected to an image read-out operation wherein they are exposed to stimulating rays in order to obtain an image signal. Because cassettes housing photographic film and stimulable phosphor sheets are different in mechanical properties, they cannot be conveyed smoothly in the electron microscope. Therefore, in the electron microscope wherein photographic film and stimulable phosphor sheets are used selectively, a magazine for housing photographic film and a magazine for housing stimulable phosphor sheets must be provided independently from each other. Also, a conveyance system for photographic film and a conveyance system for stimulable phosphor sheets must be provided independently from each other. As a result, the electron microscope becomes large in size.